Matthew T.S. Tennant

High-resolution stereoscopic digital fundus photography versus contact lens biomicroscopy for the detection of clinically significant macular edema

PURPOSE The purpose of this study was to compare high-resolution stereoscopic digital photography to contact lens biomicroscopy (CLBM) for the diagnosis of clinically significant macular edema. STUDY DESIGN Comparative, prospective, observational case series. PARTICIPANTS One hundred twenty diabetic patients. METHODS Patients underwent clinical retinal examination with CLBM by a retinal specialist. On the same day as clinical grading, patients received high-resolution stereoscopic digital imaging of the macula. The stereoscopic digital images were viewed using liquid crystal shutter goggles at least 2 months after clinical examination by a single masked grader for the presence or absence of diabetic retinopathy. MAIN OUTCOME MEASURES Presence or absence of the Early Treatment of Diabetic Retinopathy Study criteria for clinically significant macular edema (CSME) overall, CSME 1, CSME 2, CSME 3, macular edema, microaneurysms, intraretinal hemorrhage, and hard exudate. RESULTS Two hundred seven eyes of 105 patients had complete data sets from both diagnostic modalities. Exact agreement was high for all identified pathologic conditions: CSME overall, 83.6%; CSME 1, 83.6%; CSME 2, 96.1%; CSME 3, 88.5%; macular edema, 75.0%; microaneurysms, 77.9%; intraretinal hemorrhage, 83.7%; and hard exudate, 73.1%. Sensitivity ranged from 50.0% (CSME 2) to 90.6% (CSME overall). Specificity ranged from 90.0% (macular edema) to 99.0% (CSME 2). CONCLUSIONS High-resolution stereoscopic digital photography is both sensitive and specific when identifying CSME and correlates well with the accepted standard of CLBM for the diagnosis of CSME.

Improving Access to Eye Care: Teleophthalmology in Alberta, Canada

Background: Diabetic retinopathy in Alberta and throughout Canada is common, with a prevalence up to 40% in people with diabetes. Unfortunately, due to travel distance, time, and expense, a third of patients with diabetes do not receive annual dilated eye examinations by ophthalmologists, despite universal health care access. In an effort to improve access, a teleophthalmology program was developed to overcome barriers to eye care. Prior to clinical implementation, teleophthalmology technology was clinically validated for the identification of treatable levels of diabetic retinopathy. Method: Patients undergoing a teleophthalmology assessment underwent stereoscopic digital retinal photographs following pupillary dilation. Digital images were then packaged into an encrypted password-protected compressed file for uploading onto a secure server. Images were digitally unpackaged for review as a stereoscopic digital slide show and graded with a modified Early Treatment Diabetic Retinopathy Study algorithm. Reports were then generated automatically as a PDF file and sent back to the referring physician. Results: Teleophthalmology programs in Alberta have assessed more than 5500 patients (9016 visits) to date. Nine hundred thirty patients have been referred for additional testing or treatment. Approximately 2% of teleophthalmology assessments have required referral for in-person examination due to ungradable image sets, most commonly due to cataract, corneal drying, or asteroid hyalosis. Conclusions: In Alberta and throughout Canada, many patients with diabetes do not receive an annual dilated eye examination. Teleophthalmology is beneficial because patients can be assessed within their own communities. This decreases the time to treatment, allows treated patients to be followed remotely, and prevents unnecessary referrals. Health care costs may be reduced by the introduction of comprehensive teleophthalmology examinations by enabling testing and treatment to be planned prior to the patients first visit.

Identification of diabetic retinopathy by stereoscopic digital imaging via teleophthalmology: a comparison to slide film.

BACKGROUND Diabetic retinopathy is a leading cause of vision loss in North America. We compared mydriatic seven-field stereoscopic digital imaging to 100 ASA slide film photography for the identification of diabetic retinopathy via teleophthalmology. METHODS Patients from a northern Alberta community with diabetes mellitus diagnosed by a physician were asked to participate in a teleophthalmology pilot project. Patients were enrolled at four different times between October 1999 and June 2000. Seven 30 degree fields of the retina were photographed with both slide film and digital imaging (resolution 2008 x 3040 pixels) through a dilated pupil. Slide film was developed and reviewed in a masked fashion by a retinal specialist. Digital images for each patient were transmitted by satellite to Edmonton and analysed a minimum of 2 months after the original slide film. Retinal abnormalities were graded with the use of the Early Treatment Diabetic Retinopathy Study extension of the modified Airlie House classification. We calculated the sensitivity and specificity of digital imaging for the identification of features of diabetic retinopathy as seen on slide film. Pearsons correlation coefficient was also calculated. RESULTS A total of 121 patients (241 eyes), of whom 114 (94.2%) had non-insulin-dependent diabetes, participated in the study. The average duration of diabetes was 8.5 years. Of the 121 patients 57 (47.1%) had diabetic retinopathy, 12 (9.9%) had clinically significant macular edema and 2 (1.6%) had neovascularization. Pearsons correlation coefficient for the presence of retinopathy between slide film and stereoscopic digital imaging was 0.92 for microaneurysms, 0.80 for hemorrhages, 0.45 for intraretinal microvascular abnormalities, 0.32 for venous beading, 1.00 for neovascularization of the disc, 1.00 for neovascularization elsewhere in the retina and 0.97 for clinically significant macular edema (p < 0.001). The correlation between the two techniques for severe nonproliferative diabetic retinopathy (NPDR) was 0.86 and for high-risk proliferative diabetic retinopathy 1.00 (p < 0.001). INTERPRETATION Stereoscopic digital imaging has a high level of correlation with slide film for the identification of most features of diabetic retinopathy, including microaneurysms, hemorrhage, severe NPDR, high-risk proliferative diabetic retinopathy and clinically significant macular edema.

Using a patient image archive to diagnose retinopathy

Diabetes has become an epidemic that is expected to impact 365 Million people worldwide by 2025. Consequently, diabetic retinopathy is the leading cause of blindness in the industrialized world today. If detected early, treatments can preserve vision and significantly reduce debilitating blindness. Through this research we are developing and testing a method for automating the diagnosis of retinopathy in a screening environment using a patient archive and digital fundus imagery. We present an overview of our content-based image retrieval (CBIR) approach and provide performance results for a dataset of 98 images from a study in Canada when compared to an archive of 1,355 patients from a study in the Netherlands. An aggregate performance of 89% correct diagnosis is achieved, demonstrating the potential of automated, web-based diagnosis for a broad range of imagery collected under different conditions and with different cameras.

Optometric Referrals to Retina Specialists: Evaluation and Triage via Teleophthalmology

A retrospective noncomparative consecutive case series was conducted to evaluate the clinical outcomes of a novel teleophthalmology program linking optometrists to retina specialists in Alberta, Canada. One hundred seventy-one patients, referred by optometrists via teleophthalmology to a group retina practice between June 2004 and May 2006 underwent stereoscopic, mydriatic digital photography. Images were transmitted to a secure Web server and analyzed by a retina specialist. Diagnosis and recommendations were sent back to the optometrist and, if necessary, patients were referred for additional testing and clinical evaluation. A chart review of all clinical encounters was performed and the data was tabulated. Demographic features, diagnosis, testing, treatment, distance and time traveled by patient, durations between telemedicine referral, teleophthalmology consultation, in-person consultation, testing, and treatment were recorded. One hundred seventy patients were assessed via teleophthalmology for a total of 190 consultations. Eighty-nine patients (52.0%) required conventional in-person consultation with a referral completion success of 92.1% (82 patients). Fifty of these patients underwent additional diagnostic testing including fluorescein angiography (41), optical coherence tomography (14), laboratory testing (5), visual fields (2), carotid Doppler ultrasound (2), and ocular ultrasound (2). Twenty-five patients required surgical or medical treatment including focal argon laser (10), photodynamic therapy (8), panretinal photocoagulation (2), vitrectomy (2), scleral buckle (1), and other procedures (8). Average wait time between telemedicine referral and teleophthalmology review of images by the retina specialist was 1.9 days (maximum = 20 days). For those patients requiring office evaluation, the average wait time between teleophthalmology referral and in-person evaluation was 25.1 days. Twenty-one of the 25 patients (84.0%) requiring treatment underwent examination, testing, and treatment in a single day. When compared to conventional consultation methods, teleophthalmology reduced average travel distance and time by 219.1 km and 2.7 hours, respectively. Teleophthalmology reduced office visits to the retina specialist by 48% while improving the efficiency of clinical examination, testing, and treatment. Patients benefited through reduced travel time and distance.

JPEG compression of stereoscopic digital images for the diagnosis of diabetic retinopathy via teleophthalmology

BACKGROUND Canadas vast size and remote rural communities represent a significant hurdle for successful monitoring and evaluation of diabetic retinopathy. Teleophthalmology may provide a solution to overcome this problem. We investigated the application of Joint Photographic Experts Group (PEG) compression to digital retinal images to determine whether JPEG compression could reduce file sizes while maintaining sufficient quality and detail to accurately diagnose diabetic retinopathy. METHODS All 20 patients with type 2 diabetes mellitus assessed at a 1-day teleophthalmology clinic in northern Alberta were enrolled in the study. Following pupil dilation, seven 30 degrees fields of each fundus were digitally photographed at a resolution of 2008 x 3040 pixels and saved in uncompressed tagged image file format (TIFF). The files were compressed approximately 55x and 113x their original size using JPEG compression. A reviewer in Edmonton randomly viewed all original TIFF images along with the compressed JPEG images in a masked fashion for image quality and for specific diabetic retinal pathology in accordance with Early Treatment Diabetic Retinopathy Study standards. The level of diabetic retinopathy and recommendations for clinical follow-up were also recorded. Exact agreement and weighted kappa statistics, a measure of reproducibility, were calculated. RESULTS Exact agreement between the compressed JPEG images and the TIFF images was high (75% to 100%) for all measured variables at both compression levels. Reproducibility was good to excellent at both compression levels for the identification of diabetic retinal abnormalities (K = 0.45-1), diagnosis of level of retinopathy (kappa = 0.73-1) and recommended follow-up (kappa = 0.64-1). INTERPRETATION The application of JPEG compression at ratios of 55:1 and 113:1 did not significantly interfere with the identification of specific diabetic retinal pathology, diagnosis of level of retinopathy or recommended follow-up. These results indicate that JPEG compression at ratios as high as 113:1 has the potential to reduce storage requirements without interfering with the accurate and reproducible teleophthalmologic diagnosis of diabetic retinopathy. This pilot project demonstrates the potential for JPEG compression within a digital teleophthalmology viewing system.

Tele-Ophthalmology via Stereoscopic Digital Imaging: A Pilot Project

Diabetic eye disease is present in remote communities across Canada. A pilot study was designed to assess the feasibility of stereoscopic digital imaging to identify levels of diabetic retinopathy via teleophthalmology. Diabetic patients were assessed for diabetic retinopathy by seven field stereoscopic digital imaging through a dilated pupil. Images were transferred by satellite to a tertiary eye center for review by a retinal specialist. Images were viewed stereoscopically on a video monitor, with grading of all images using a modified Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Patients found to have treatable diabetic retinopathy were transferred to a tertiary eye center for assessment and treatment by a retinal specialist. One hundred patients (199 eyes) had stereoscopic digital imaging of the retina. Microaneurysms were identified in 70 eyes, hard exudates in 31 eyes. Two eyes were identified with neovascularization of the disc (NVD) and 15 eyes with clinically significant macular edema (CSME). All eyes identified by stereoscopic digital imaging with treatable disease were confirmed by clinical examination with contact lens biomicroscopy. Stereoscopic digital imaging of the retina enables the identification of diabetic retinopathy. Further research is needed to delineate the sensitivity and specificity of stereoscopic digital imaging when compared to slide film and clinical examination.

The prevalence of diabetic retinopathy as identified by teleophthalmology in rural Alberta

OBJECTIVE The purpose of this study was to assess the prevalence of diabetic retinopathy (DR) as identified by teleophthalmology in a sample population of people with diabetes living in rural Alberta and to identify the risks and benefits of a teleophthalmology program for these patients. DESIGN Retrospective consecutive case series. PARTICIPANTS Three hundred ninety-four diabetic patients (788 eyes). METHODS Medical histories were obtained, following which patients underwent visual acuity and intraocular pressure measurements and stereoscopic, 7-field, digital retinal photography. Images were graded by ophthalmologists in Edmonton, Alta., according to a modified Early Treatment Diabetic Retinopathy Study scoring template. Diagnosis, treatment, and follow-up recommendations were communicated to local health care providers and data were collected for review. RESULTS Three hundred ninety-four patients (788 eyes) were assessed via 593 teleophthalmology visits over the 3-year period. DR was identified in 27.2% of patients (2.3% with proliferative DR and 24.9% with nonproliferative DR). A variety of other diagnoses, independent of DR, were also made. Recommendations for follow-up teleophthalmology and in-person referral were completed in 76.8% and 87.3% of patients, respectively, although many were completed later than was recommended. Teleophthalmology saved approximately 450 round trips from Edson to the nearest urban centre (Edmonton) over the 2-year period, equating to approximately 1900 hours and 180 000 km of driving. CONCLUSIONS Teleophthalmology can effectively identify DR while reducing travel time and distance for patients with diabetes living in a rural community. However, many patients did not follow up or attend referral appointments in a timely fashion, underscoring the need for ongoing quality assessment.

Long-term Outcomes For Optic Disk Pit Maculopathy After Vitrectomy

Purpose: To evaluate the efficacy of pars plana vitrectomy for congenital optic disk pit maculopathy with various adjuvant techniques, including gas tamponade, internal limiting membrane peel, and temporal optic disk endolaser in a multicenter study with long-term follow-up. Methods: A retrospective chart review was performed to identify eyes that underwent surgical repair for congenital optic disk pits and serous macular detachment with or without macular retinoschisis from four retinal centers across Canada from 2003 to 2013. Data collected included surgeries performed, preoperative and postoperative vision, central retinal thickness, and presence or absence of subretinal fluid. Optical coherence tomography was used to define anatomical success (i.e., foveal reattachment). Results: Thirty-two eyes of 32 patients with optic disk pits and serous macular detachments were identified that had undergone surgical repair. All eyes underwent pars plana vitrectomy and induction of posterior vitreous detachment if one was not present. Additional procedures performed on occasion included internal limiting membrane peel (n = 8), temporal optic disk pits endolaser (n = 7), and gas tamponade (air, C3F8 or SF6; n = 31). After vitrectomy surgery, foveal attachment was achieved in 26 of 32 eyes (81.3%). The average number of surgeries required was 1.4 ± 0.6, with a maximum of 3 vitrectomies (n = 2). Mean change in best-corrected visual acuity was −0.47 ± 0.54 logMAR units, which corresponds to approximately 5 lines of visual improvement (P < 0.001). Median time to reattachment was 416 days. Preoperative vision, preoperative symptom days, and age were not associated with postoperative reattachment. Similarly, internal limiting membrane peel and temporal endolaser were not associated with postoperative reattachment, nor was there a difference between air and SF6 and C3F8 gas tamponade. Elevated preoperative central retinal thickness was associated with a lower chance of postoperative reattachment (P = 0.007) and was also the best prognostic indicator of success (P = 0.039). Conclusion: Vitrectomy for macular detachment due to optic disk pit has good long-term success and results in an improvement in visual acuity. However, adjuvant techniques such as internal limiting membrane peel and temporal endolaser may not improve outcomes, nor does there seem to be a difference between short- and long-acting gases. Patients should be made aware that it can take more than a year and multiple surgeries to achieve foveal reattachment and that increased baseline central retinal thickness is a poor prognostic sign.

Prevalence and impact of depressive symptoms in patients with age-related macular degeneration.

OBJECTIVE This study sought to identify the point prevalence of depressive symptoms, quality-of-life (QOL) impairment, and demographic parameters associated with depression in patients with age-related macular degeneration (AMD) attending a retina clinic in Edmonton, Alberta. DESIGN A cross-sectional design was used. METHODS Consecutive patients with AMD were invited to participate in the study. Demographic data, as well as ophthalmic, medical, and psychiatric histories, were collected. Participants completed the Center for Epidemiological Studies Depression Scale (CES-D) and the Visual Function Questionnaire (VFQ-25) scales to quantify the burden of depressive symptoms and vision-related QOL impairment. RESULTS The study enrolled 101 patients, of whom 7 (6.9%) had a previous history of depression. Twenty (21.3%) of the remaining patients endorsed severe symptoms of depression that had not yet been diagnosed. Significant differences in vision-related QOL between depressed and not depressed patients were identified. Depressed patients were also found to have worse visual acuity (p = 0.047) and were less likely to live with others (p = 0.020) than those who were not depressed. CONCLUSIONS After excluding patients with a history of diagnosed depression, 20 (21.3%) patients demonstrated severe symptoms of depression. Development of depression screening protocols for patients with AMD would improve identification and referral of patients at risk. The finding that patients who lived with others had a lower prevalence of depressive symptoms suggests that further research into the relationship between mood symptoms and environmental supports is merited.